Indoor unit of air conditioner

ABSTRACT

The present invention provides indoor unit of air conditioner including a plurality of heat-exchangers, main-unit casing that accommodates heat-exchangers and includes suction air duct extending from air inlet to heat-exchangers and blowout air duct extending from heat-exchangers to air outlet, and air blower that is provided in blowout air duct and blows out air taken in from air inlet, from air outlet after having air passed through heat-exchangers. In indoor unit, heat-exchangers include rear-side heat-exchanger arranged opposite to air blower on upper side in main-unit casing with lower end thereof being arranged on rear surface side of main-unit casing, backplane that constitutes rear-side duct wall of blowout air duct is provided on rear surface side of main-unit casing, and heat transfer unit that transfers heat of air before passing through heat-exchangers or heat of air outside main-unit casing to backplane is provided in main-unit casing

FIELD

The present invention relates to, in an indoor unit of an air conditioner, a structure of preventing occurrence of dew condensation in an air duct in a main unit of the indoor unit.

BACKGROUND

For example, in an indoor unit of an air conditioner that adjusts the temperature and humidity of a room, there is a case where dew condensation water generated in a heat exchanger of the indoor unit adheres on a wall surface of an air duct wall of the indoor unit to cool the air duct wall, thereby causing dew condensation on the air duct wall. Conventionally, in order not to generate such dew condensation, there have been proposed a structure in which the vicinity of a drainage path of an air duct wall has a double structure as disclosed in Patent Literature 1 and a structure in which a drainage path is inclined to prevent accumulation of dew condensation water as disclosed in Patent Literature 2. Furthermore, there have also been proposed a structure in which heat insulating properties are improved by increasing the thickness of a casing to prevent occurrence of dew condensation as disclosed in Patent Literature 3 and a structure in which a heat insulating member made of a material such as foamed polystyrene is applied to a rear side of a portion where dew condensation is generated and a structure in which a hollow structure is provided to the rear side of the portion where dew condensation is generated to provide heat insulation as disclosed in Patent Literature 4.

CITATION LIST Patent Literatures

-   Patent Literature 1: Japanese Patent Application Laid-open No.     H10-103706 -   Patent Literature 2: Japanese Patent Application Laid-open No.     2000-161705 -   Patent Literature 3: Japanese Patent Application Laid-open No.     2001-082791 -   Patent Literature 4: Japanese Patent Application Laid-open No.     H11-159791

SUMMARY Technical Problem

However, the conventional techniques described above have a structure in which occurrence of dew condensation is prevented by improving heat insulating properties by using a heat insulating member or the like, to deal with the problem of an air duct wall being cooled by dew condensation water generated in a heat exchanger. Therefore, there has been a problem such that the number of parts is increased to increase the manufacturing cost.

The present invention has been achieved in view of the above problems, and an object of the present invention is to suppress generation of dew condensation without using any heat insulating member or the like and without increasing the manufacturing cost, with respect to dew condensation generated on a wall surface of an air duct wall.

Solution to Problem

In order to solve the aforementioned problems and attain the aforementioned object, according to an aspect of the present invention, the indoor unit of an air conditioner is provided with: a plurality of heat exchangers having a refrigerant circulates therein; a main-unit casing that accommodates the heat exchangers and includes a suction air duct extending from an air inlet to the heat exchangers and a blowout air duct extending from the heat exchangers to an air outlet; and an air blower that is provided in the blowout air duct and blows out air taken in from the air inlet, from the air outlet after having the air passed through the heat exchangers, wherein the heat exchangers include a rear-side heat exchanger arranged opposite to the air blower on an upper side in the main-unit casing with a lower end thereof being arranged on a rear surface side of the main-unit casing, a backplane that constitutes a rear-side duct wall of the blowout air duct is provided on a rear surface side of the main-unit casing, and a heat transfer unit that transfers heat of air before passing through the heat exchangers or heat of air outside the main-unit casing to the backplane, is provided in the main-unit casing.

Advantageous Effects of Invention

According to the indoor unit of an air conditioner of the present invention, a backplane that constitutes a rear-side duct wall of a blowout air duct is provided on a rear surface side of a main-unit casing. A heat transfer unit transfers the heat of air before passing through heat exchangers or air outside the main-unit casing to the backplane. With this configuration, too much cooling of the blowout air duct can be regulated, and generation of dew condensation on a duct wall surface can be suppressed without using any heat insulating member or the like and without increasing the manufacturing cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal sectional view of an indoor unit of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a part A in FIG. 1 in an enlarged scale.

FIG. 3 is an enlarged sectional view of a portion corresponding to the part A in FIG. 1 of an indoor unit of a conventional air conditioner that is shown for comparison.

FIG. 4 is an enlarged sectional view of an indoor unit of an air conditioner according to a second embodiment of the present invention.

FIG. 5-1 is an enlarged sectional view of an indoor unit of an air conditioner according to a third embodiment of the present invention.

FIG. 5-2 is an enlarged sectional view of a first modification of the third embodiment of the present invention.

FIG. 5-3 is an enlarged sectional view of a second modification of the third embodiment of the present invention.

FIG. 6 is an enlarged sectional view of an indoor unit of an air conditioner according to a fourth embodiment of the present invention.

FIG. 7-1 is an enlarged sectional view of an example of combining the structure of the first embodiment and that of the third embodiment of the present invention.

FIG. 7-2 is an enlarged sectional view of an example of combining the first embodiment and the first modification of the third embodiment of the present invention.

FIG. 7-3 is an enlarged sectional view of an example of combining the first embodiment and the second modification of the third embodiment of the present invention.

FIG. 8 is an enlarged sectional view of an example of combining the structure of the second embodiment and that of the third embodiment of the present invention.

FIG. 9 is an enlarged sectional view of an example of combining the structure of the first embodiment and that of the fourth embodiment of the present invention.

FIG. 10 is an enlarged sectional view of an example of combining the structure of the second embodiment and that of the fourth embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of an indoor unit of an air conditioner according to the present invention will be explained below in detail with reference to the accompanying drawings. The present invention is not limited by these embodiments.

First Embodiment

An overall structure of an indoor unit of an air conditioner is explained first. FIG. 1 is a longitudinal sectional view of an indoor unit of an air conditioner according to a first embodiment of the present invention. FIG. 2 is an enlarged view of a part A in FIG. 1 in an enlarged scale. The indoor unit according to the present embodiment includes an air blower 4, heat exchangers (a front-side heat exchanger 3 and a rear-side heat exchanger 8), and a main-unit casing 1 that accommodates the air blower 4 and the heat exchangers 3 and 8.

In the cross section shown in FIG. 1, the air blower 4 is arranged substantially in the center of the main-unit casing 1. The heat exchanger is arranged to surround the air blower 4 and includes the front-side heat exchanger 3 and the rear-side heat exchanger 8. The front-side heat exchanger 3 and the rear-side heat exchanger 8 are connected to a heat source unit (outdoor unit) (not shown) by a pipe, and a refrigerant supplied from the heat source unit circulates in these heat exchangers.

A suction air duct 17 extending from an air inlet 19 to the front-side heat exchanger 3 and the rear-side heat exchanger 8; and a blowout air duct 18 extending from the front-side heat exchanger 3 and the rear-side heat exchanger 8 to an air outlet 20, are formed in the main-unit casing 1. The air blower 4 is a sirocco fan-type air blower having a cylindrical multi-blade fan, and blows out air sucked from a central part to the circumference by a centrifugal force. The air blower 4 is provided in the blowout air duct 18 to cause air taken in from the air inlet 19 to pass through the heat exchanger, and then blows out the air from the air outlet 20. At the time of a cooling operation and a dehumidifying operation, the air taken in from the air inlet 19 is cooled by the front-side heat exchanger 3 and the rear-side heat exchanger 8 and is blown out from the air outlet 20.

A filter 7 for removing dust and the like is arranged in the air inlet 19. A horizontal wind-direction vane 5 that switches the wind direction horizontally and a vertical wind-direction flap 6 that switches the wind direction vertically are provided in the air outlet 20.

The front-side heat exchanger 3 is arranged opposite to the air blower 4 at a position on a front surface side in the main-unit casing 1 (on an inner side of a room). On the other hand, the rear-side heat exchanger 8 is arranged opposite to the air blower 4 at a position on an upper side in the main-unit casing 1 and a lower end thereof is positioned on a rear surface side of the main-unit casing 1 (on a wall side of the room).

Furthermore, a backplane 11 that constitutes a rear-side duct wall of the blowout air duct 18 is provided on the rear surface side of the main-unit casing 1. The backplane 11 is positioned below the lower end of the rear-side heat exchanger 8. In the present embodiment, the suction air duct 17 is extended to form an extended air duct 21, which extends to a rear side of the backplane 11 (FIG. 2). The extended air duct 21 is provided between a heat insulating member 10 provided at the lower end of the rear-side heat exchanger 8 and a rear wall surface 1 a of the main-unit casing 1, and includes a rear surface 11 a of the backplane 11. The extended air duct 21 communicates with the suction air duct 17, guides warm air before passing through the heat exchangers (the front-side heat exchanger 3 and the rear-side heat exchanger 8) to the rear surface 11 a of the backplane 11 as shown by a broken-line arrow C in FIG. 2, and causes the warm air to come into contact with the rear surface of the backplane 11. That is, the extended air duct 21 constitutes a heat transfer unit that transfers the heat of air before passing through the heat exchangers (the front-side heat exchanger 3 and the rear-side heat exchanger 8) to the backplane 11.

FIG. 3 is an enlarged view of a portion corresponding to FIG. 2 of an indoor unit of a conventional air conditioner that is shown for comparison. Conventionally, there has been a problem that low-temperature dew condensation water generated in the rear-side heat exchanger 8 is transferred to the backplane 11, so as to cool the backplane 11 more than being supposed to, thereby generating dew condensation in the blowout air duct 18. Conventionally, therefore, measures such as providing a drainage path 12 or the like on the rear surface of the backplane 11 have been taken; however, these measures are not good enough to achieve a satisfactory effect.

In the present embodiment, a part of the suction air duct 17 is extended to form the extended air duct 21 that extends up to the rear surface of the backplane 11. The extended air duct 21 is formed while including the rear surface of the backplane 11, and warm air before passing through the heat exchangers (the front-side heat exchanger 3 and the rear-side heat exchanger 8) is guided to the rear surface of the backplane 11 by the extended air duct 21, and the guided warm air comes into contact with the rear surface of the backplane 11. Therefore, the backplane 11 is not cooled too much, and generation of dew condensation in the blowout air duct 18 is suppressed.

Second Embodiment

FIG. 4 is a sectional view of an indoor unit of an air conditioner according to a second embodiment of the present invention. In the present embodiment, an outside-air guiding depression 22 that transfers the heat of outside air (air outside of the main-unit casing 1 of the indoor unit) to the backplane 11 is provided, instead of the extended air duct 21 according to the first embodiment. A rear wall surface 1 b of the main-unit casing 1 is deeply retreated (depressed) in a V-shape in cross section toward an inner side of the main-unit casing 1, so as to form the outside-air guiding depression 22. The outside-air guiding depression 22 is formed while including the rear surface of the backplane 11, and communicates with an external space of the main-unit casing so that outside air comes into direct contact with the rear surface 11 a of the backplane 11. That is, the outside-air guiding depression 22 constitutes a heat transfer unit that transfers the heat of outside air to the backplane 11. In the present embodiment, generally, outside air having a temperature higher than that of dew condensation water generated in the rear-side heat exchanger 8 comes into direct contact with the rear surface 11 a of the backplane 11. Therefore, the backplane 11 is warmed and not cooled too much, and thus dew condensation does not occur in the blowout air duct 18.

Third Embodiment

FIG. 5-1 is an enlarged sectional view of an indoor unit of an air conditioner according to a third embodiment of the present invention. In the present embodiment, a metal plate 23A is attached on a rear surface (outside) of the backplane 11 as a thermal-conduction promoting member, in order to improve the thermal conduction of the backplane 11. More specifically, the metal plate 23A is folded so as to cover both principal surfaces and attached on the outside of a corner portion where the rear wall surface 1 a of the main-unit casing 1 is joined to the backplane 11. The metal plate 23A is made of, for example, a material having an excellent thermal conductivity such as copper, and at least a part of the metal plate 23A is exposed to outside air of the main-unit casing 1 so as to come into contact with outside air, thereby efficiently absorbing the heat of outside air and transferring the heat to the backplane 11. Accordingly, generation of dew condensation in the blowout air duct 18 is suppressed. By providing the metal plate 23A to bridge over a portion exposed to outside air of the main-unit casing 1 and the backplane 11, the heat of outside air can be effectively transferred to the backplane 11.

FIG. 5-2 is an enlarged sectional view of a first modification of the third embodiment of the present invention. In this modification, a metal plate 23B as a thermal-conduction promoting member is attached on an inner surface 11 b (on the side of the blowout air duct 18) of the backplane 11. In the metal plate 23B having such a configuration, the heat-transfer capability of the backplane 11 is improved. Therefore, excessive temperature reduction in a part of the backplane 11 is suppressed, thereby suppressing generation of dew condensation in the blowout air duct 18. It is effective as the metal plate 23B is arranged to span over a portion of the backplane 11 where the temperature does not decrease relatively (a portion where the rear surface comes into contact with outside air) and a portion where the temperature decreases due to dew condensation water generated in the rear-side heat exchanger 8.

FIG. 5-3 is an enlarged sectional view of a second modification of the third embodiment of the present invention. A metal plate 23C as a thermal-conduction promoting member is arranged by being embedded inside the backplane 11. Even in the metal plate 23C having such a configuration, effects substantially identical to those of FIG. 5-2 can be achieved, and because the metal plate 23C is embedded inside the backplane 11, the metal plate 23C is hardly eroded, thereby improving its durability.

The thermal-conduction promoting member is not limited to a metal plate, and for example, a tape-like member (a metal tape) such as a metal foil acquired by applying an adhesive having a high thermal conductivity to one surface of a thin member can be used.

Fourth Embodiment

FIG. 6 is an enlarged sectional view of an indoor unit of an air conditioner according to a fourth embodiment of the present invention. In the present embodiment, as a heat transfer unit, a plate-shaped member 24 is arranged upright on a rear surface of the backplane 11. The plate-shaped member 24 is made of a material having an excellent thermal conductivity, and is exposed to outside air. Therefore, the heat of outside air is favorably transferred to the backplane 11 via the plate-shaped member 24, and thus the backplane 11 is not cooled too much and dew condensation is not generated in the blowout air duct 18. For example, the plate-shaped member 24 is fixed by an adhesive having a high thermal conductivity. When the plate-shaped member 24 is made of a material having a thermal conductivity higher than that of the material of the backplane 11, the plate-shaped member 24 can achieve a predetermined effect.

The first to fourth embodiments can be combined with each other. FIG. 7-1 is an enlarged sectional view of an example of combining the structure of the first embodiment and that of the third embodiment of the present invention. The indoor unit includes the extended air duct 21 that extends to the rear surface of the backplane 11 and works as a heat transfer unit that transfers the heat of air before passing through the heat exchanger to the backplane 11, and the metal plate 23A as a thermal-conduction promoting member. FIG. 7-2 is an enlarged sectional view of an example of combining the first embodiment and the first modification of the third embodiment of the present invention. The indoor unit similarly includes the extended air duct 21 that works as a heat transfer unit and the metal plate 23B as a thermal-conduction promoting member. FIG. 7-3 is an enlarged sectional view of an example of combining the first embodiment and the second modification of the third embodiment of the present invention. The indoor unit similarly includes the extended air duct 21 that works as a heat transfer unit and the metal plate 23C as a thermal-conduction promoting member.

FIG. 8 is an enlarged sectional view of an example of combining the structure of the second embodiment and that of the third embodiment of the present invention. The indoor unit includes the outside-air guiding depression 22 that works as a heat transfer unit that transfers the heat of outside air to the backplane 11, and the metal plate 23A as a thermal-conduction promoting member. FIG. 9 is an enlarged sectional view of an example of combining the structure of the first embodiment and that of the fourth embodiment of the present invention. The indoor unit includes the extended air duct 21 that extends to the rear surface of the backplane 11 and works as a heat transfer unit that transfers the heat of air before passing through the heat exchanger to the backplane 11, and the plate-shaped member 24 that is arranged upright on a rear surface of the backplane 11 and works as a heat transfer unit that transfers the heat of outside air to the backplane 11. FIG. 10 is an enlarged sectional view of an example of combining the structure of the second embodiment and that of the fourth embodiment of the present invention. The indoor unit includes the outside-air guiding depression 22 that works as the heat transfer unit that transfers the heat of outside air to the backplane 11, and the plate-shaped member 24 that is arranged upright on the rear surface of the backplane 11 and works as the heat transfer unit that transfers the heat of outside air to the backplane 11. These examples also have effects achieved by each of the combined embodiments, and effects even better than those achieved by combining these effects can be obtained due to the synergy of these combinations.

INDUSTRIAL APPLICABILITY

As described above, the indoor unit of an air conditioner according to the present invention is useful to be applied to an indoor unit of an air conditioner having a rear-side heat exchanger arranged on an upper side in a main-unit casing with a lower end thereof being positioned on a rear surface side of the main-unit casing, and a backplane that constitutes a rear-side duct wall of a blowout air duct on the rear surface side of the main-unit casing.

REFERENCE SIGNS LIST

-   -   1 MAIN-UNIT CASING     -   3 FRONT-SIDE HEAT EXCHANGER     -   4 AIR BLOWER     -   5 HORIZONTAL WIND-DIRECTION VANE     -   6 VERTICAL WIND-DIRECTION FLAP     -   7 FILTER     -   8 REAR-SIDE HEAT EXCHANGER     -   10 HEAT INSULATING MEMBER     -   11 BACKPLANE     -   12 DRAINAGE PATH     -   17 SUCTION AIR DUCT     -   18 BLOWOUT AIR DUCT     -   19 AIR INLET     -   20 AIR OUTLET     -   21 EXTENDED AIR DUCT (HEAT TRANSFER UNIT)     -   22 OUTSIDE-AIR GUIDING DEPRESSION (HEAT TRANSFER UNIT)     -   23 METAL PLATE (THERMAL-CONDUCTION PROMOTING MEMBER)     -   24 PLATE-SHAPED MEMBER (HEAT TRANSFER UNIT) 

1. An indoor unit of an air conditioner comprising: a plurality of heat exchangers having a refrigerant circulates therein; a main-unit casing that accommodates the heat exchangers and includes a suction air duct extending from an air inlet to the heat exchangers and a blowout air duct extending from the heat exchangers to an air outlet; and an air blower that is provided in the blowout air duct and blows out air taken in from the air inlet, from the air outlet after having the air passed through the heat exchangers, wherein the heat exchangers include a rear-side heat exchanger arranged opposite to the air blower on an upper side in the main-unit casing with a lower end thereof being arranged on a rear surface side of the main-unit casing, a backplane that constitutes a rear-side duct wall of the blowout air duct is provided on a rear surface side of the main-unit casing, and a heat transfer unit that transfers heat of air before passing through the heat exchangers or heat of air outside the main-unit casing to the backplane, is provided in the main-unit casing.
 2. The indoor unit of an air conditioner according to claim 1, wherein the heat transfer unit is an extended suction air duct that is formed between the rear-side heat exchanger and the backplane in the main-unit casing while including a rear surface of the backplane, communicates with the suction air duct, and guides air before passing through the heat exchangers to come into contact with the rear surface of the backplane.
 3. The indoor unit of an air conditioner according to claim 1, wherein the heat transfer unit is an outside-air guiding depression that is formed between the rear-side heat exchanger and the backplane in the main-unit casing while including a rear surface of the backplane, communicates with an external space of the main-unit casing, and guides outside air to the rear surface of the backplane to come into contact therewith.
 4. The indoor unit of an air conditioner according to claim 1, wherein the heat transfer unit is a plate-shaped member arranged upright on a rear surface of the backplane, with at least a part thereof being exposed to outside air.
 5. The indoor unit of an air conditioner according to claim 1, wherein the heat transfer unit is an extended suction air duct that is formed between the rear-side heat exchanger and the backplane in the main-unit casing while including a rear surface of the backplane, communicates with the suction air duct, and guides air before passing through the heat exchangers to come into contact with the rear surface of the backplane, and a plate-shaped member arranged upright on the rear surface of the backplane, with at least a part thereof being exposed to outside air.
 6. The indoor unit of an air conditioner according to claim 1, wherein the heat transfer unit is an outside-air guiding depression that is formed between the rear-side heat exchanger and the backplane in the main-unit casing while including a rear surface of the backplane, communicates with an external space of the main-unit casing, and guides outside air to the rear surface of the backplane to come into contact therewith, and a plate-shaped member arranged upright on the rear surface of the backplane, with at least a part thereof being exposed to outside air.
 7. The indoor unit of an air conditioner according to claim 1, further comprising a thermal-conduction promoting member that is overlapped and attached on a principal plane of the backplane or embedded in the backplane along the principal plane, to promote thermal conduction of the backplane.
 8. The indoor unit of an air conditioner according to claim 7, wherein the thermal-conduction promoting member is a metal plate or a metal tape. 